Ultra and beolab speakers and sub

[noddybrown]

Moving my ultra from Denon amp and passive kef speakers direct to beolab 6000 powered speakers.

How best to add a sub to this?

Guessing direct to the sub out on Ultra?

But I thought that speakers self adjust if they know there is sub attached.
As planned, powered speakers will not adjust to new sub?

What is the solution please?

Thank you

Neil
UK